U.S. patent application number 11/736537 was filed with the patent office on 2008-10-23 for complex wire formed devices.
This patent application is currently assigned to Lazarus Effect, Inc.. Invention is credited to Brian B. MARTIN.
Application Number | 20080262532 11/736537 |
Document ID | / |
Family ID | 39875896 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080262532 |
Kind Code |
A1 |
MARTIN; Brian B. |
October 23, 2008 |
COMPLEX WIRE FORMED DEVICES
Abstract
The devices and methods described herein relate to jointless
construction of complex structures. Such devices have applicability
in through-out the body, including clearing of blockages within
body lumens, such as the vasculature, by addressing the frictional
resistance on the obstruction prior to attempting to translate
and/or mobilize the obstruction within the body lumen
Inventors: |
MARTIN; Brian B.; (Boulder
Creek, CA) |
Correspondence
Address: |
LEVINE BAGADE HAN LLP
2483 EAST BAYSHORE ROAD, SUITE 100
PALO ALTO
CA
94303
US
|
Assignee: |
Lazarus Effect, Inc.
Felton
CA
|
Family ID: |
39875896 |
Appl. No.: |
11/736537 |
Filed: |
April 17, 2007 |
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 2017/2215 20130101;
A61B 17/32056 20130101; A61B 2017/2212 20130101; A61B 2017/2217
20130101; A61B 2017/00867 20130101; A61F 2/013 20130101; A61B
17/221 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 29/00 20060101
A61M029/00 |
Claims
1.-58. (canceled)
59. An apparatus comprising: a microcatheter having a size and
flexibility to navigate within a neurovascular region of the
patient; a plurality of wires joined into a main bundle and
extending from the microcatheter, where at least a first portion of
the plurality of wires diverge from the main bundle to form a first
shape; a plurality of subsets of wires diverging from the first
shape; a second shape formed by the convergence of the plurality of
subsets of wires; where at least one wire diverges from the second
shape to form a blood permeable member shape; where the first shape
has a first expanded profile when unconstrained, such that on
deployment in the neurovascular region the first shape expands
towards the first expanded profile; where the second shape is
collapsible to fit within the microcatheter and has a second
expanded profile when unconstrained, such that on deployment in the
neurovascular region the second shape expands towards the second
expanded profile; where the plurality of subsets of wires extends
between the first and second shapes, and are spaced apart on each
respective shape such that spacing the first and second shapes
causes the individual subsets to move towards a wall of a vessel in
the neurovascular region; and where the blood permeable filter
member shape is collapsible to fit within the microcatheter and
expandable to expand in the neurovascular region upon
deployment.
60. The apparatus of claim 59, where a second portion of the
plurality of wires diverges from the main bundle separately from
the first portion to form the first shape.
61. The medical device of claim 59, where each shaped section is
jointless
62. The apparatus of claim 59, where each transition between each
shape is jointless.
63. The apparatus of claim 59, where the first shape is
non-planar.
64. The apparatus of claim 59, where the second shape is
non-planar.
65. The apparatus of claim 59, where the first shape comprises a
shape selected from the group consisting of a circle, an arcuate
shape, a partial circular shape, a loop, an oval, a square, a
rectangle, a polygon, an overlapping loop, a pair of semi-circles,
a flower shape, and a FIG. 8.
66. The apparatus of claim 59, where the second shape comprises a
shape selected from the group consisting of a circle, an arcuate
shape, a partial circular shape, a loop, an oval, a square, a
rectangle, a polygon, an overlapping loop, a pair of semi-circles,
a flower shape, and a FIG. 8.
67. The apparatus of claim 59, where the main bundle extends for a
length sufficient to withdraw the device from a body of a
patient.
68. The apparatus of claim 59, where the plurality of wires
includes at least a first wire and a second wire where the first
and second wire each has different characteristics.
69. The apparatus of claim 68, where the characteristics are
selected from a group consisting of material, cross-sectional
shape, and cross-sectional size.
70. The apparatus of claim 68, where the characteristics are
selected from a group consisting of brittleness, ductility,
elasticity, hardness, malleability, plasticity, strength, and
toughness.
71. The apparatus of claim 59, where the plurality of wires forming
the main bundle comprises at least one shape memory alloy wire.
72. The apparatus of claim 59, where the plurality of wires forming
the main bundle comprises at least one super-elastic wire.
73. The apparatus of claim 59, where the plurality of wires forming
the main bundle comprises at least one polymeric wire.
74. The apparatus of claim 59, where the plurality of wires forming
the main bundle comprises at least one wire comprising a metal
alloy.
75. The apparatus of claim 74, where the metal alloy comprises an
alloy selected from the group consisting of stainless steel,
titanium, platinum, gold, iridium, tantalum, nitinol, and
combinations thereof.
76. The medical device of claim 59, where at least one wire
comprises a shape selected from the group consisting of a circle,
an oval, a rectangular shape, and a D-shape.
77. The apparatus of claim 59, further comprising at least one
radiopaque material located on the first and/or second shape.
78. The apparatus of claim 59, where the plurality of wires in the
main bundle are braided.
79. The apparatus of claim 59, where the plurality of wires in the
main bundle are wound.
80. The apparatus of claim 59, where the first shape is rotatable
relative to the second shape, such that upon rotation the subsets
of wires form a mesh or helical pattern.
81. The apparatus of claim 59, where at least one of the wires
diverging from the main bundle returns to the main bundle after
forming at least one of the shapes or blood permeable filter member
in the device.
82. The apparatus of claim 59, where each of the wires diverging
from the main bundle returns to the main bundle after forming at
least one of the shapes or blood permeable filter member in the
device.
83. A medical device for delivery through a catheter, the medical
device comprising device comprising: a first main bundle comprised
of a plurality of wires; a first shape formed by a divergence of
the plurality of wires into a plurality of individual first subsets
of wires, and where each first subset of wires diverges to form a
network of wires, where the network of wires converges to form a
plurality of individual second subset of wires, and where each
second subset of wires converges to form a second main bundle;
where a region of the device from the first shape to the second
shape forms a basket structure having no joints; and where the
first and second shape each form a three dimensional structure.
84. The apparatus of claim 83, network of wires comprise individual
single wires.
85. The apparatus of claim 83, where the first shape comprises a
shape selected from the group consisting of a circle, an arcuate
shape, a partial circular shape, a loop, an oval, a square, a
rectangle, a polygon, an overlapping loop, a pair of semi-circles,
a flower shape, and a figure 8.
86. The apparatus of claim 83, where the second shape comprises a
shape selected from the group consisting of a circle, an arcuate
shape, a partial circular shape, a loop, an oval, a square, a
rectangle, a polygon, an overlapping loop, a pair of semi-circles,
a flower shape, and a figure 8.
87. The medical device of claim 83, where the first shape is
rotatable relative to the second shape, such that upon rotation the
network of individual wires forms a mesh or helical pattern.
88. The apparatus of claim 83, where each transition between each
shape is jointless.
89. The apparatus of claim 83, where each individual single wire
comprises a plurality of filaments.
90. The apparatus of claim 83, where the first main bundle and the
second main bundle converge.
91. The apparatus of claim 83, where main bundle of wires includes
at least a first wire and a second wire where the first and second
wire each has different characteristics.
92. The apparatus of claim 91, where the characteristics are
selected from a group consisting of material, cross-sectional
shape, and cross-sectional size.
93. The apparatus of claim 91, where the characteristics are
selected from a group consisting of brittleness, ductility,
elasticity, hardness, malleability, plasticity, strength, and
toughness.
Description
FIELD OF THE INVENTION
[0001] The devices described herein are constructed in wire form
where the wires diverge from a main bundle to form a variety of
shapes that form a composite device. The benefit of such a
diverging wire construction is that the composite complex device
can be of a "joint-less" construction. Such devices have
applicability in through-out the body, including clearing of
blockages within body lumens, such as the vasculature, by
addressing the frictional resistance on the obstruction prior to
attempting to translate and/or mobilize the obstruction within the
body lumen.
BACKGROUND OF THE INVENTION
[0002] Many medical device applications require advancement of
device in a reduced profile to a remote site within the body, where
on reaching a target site, the device assumes or is deployed into a
relatively larger profile. Applications in the cerebral vasculature
are one such example of medical procedures where a catheter
advances from a remote part of the body (typically a leg) through
the vasculature and into the cerebral region of the vasculature to
deploy a device. Accordingly, the deployed devices must be capable
of achieving a larger profile while being able to fit within a
small catheter or microcatheter. In addition, the degree to which a
physician is limited in accessing remote regions of the cerebral
vasculature is directly related to the limited ability of the
device to constrain into a reduced profile for delivery.
[0003] Treatment of ischemic stroke is one such area where a need
remains to deliver a device in a reduced profile and deploy the
device to ultimately remove a blockage in an artery leading to the
brain. Left untreated, the blockage causes a lack of supply of
oxygen and nutrients to the brain tissue. The brain relies on its
arteries to supply oxygenated blood from the heart and lungs. The
blood returning from the brain carries carbon dioxide and cellular
waste. Blockages that interfere with this supply eventually cause
the brain tissue to stop functioning. If the disruption in supply
occurs for a sufficient amount of time, the continued lack of
nutrients and oxygen causes irreversible cell death (infarction).
Accordingly, immediate medical treatment of an ischemic stroke is
critical for the recovery of a patient.
[0004] Naturally, areas outside of ischemic stroke applications can
also benefit from devices that can assume a profile for ultimate
delivery to remote regions of the body.
[0005] Regardless of the area where the device is to be used, when
fabricating such a device the joints between adjacent shapes or
sections of the device often impede the ability of the device to
assume a sufficiently reduced profile or interfere with the
geometry/stiffness of the device causing problems when navigating
the device through the body. Also, joints lead to potential failure
locations, and may lead to fractured and embolized components
within the body. Such joints may include welded, glued, or
otherwise separately joined pieces into one or more points of
connection.
[0006] Accordingly, a need remains for devices that can assume
deployed configurations and are fabricated to eliminate or reduce
the number of joints and/or connection points in the device. Doing
so allows the device to have a compact and smooth configuration
making it easier for delivery through a microcatheter, and leads to
a safer device less prone to breaking or embolizing.
SUMMARY OF THE INVENTION
[0007] The examples discussed herein show the inventive device in a
form that is suitable to retrieve obstructions or clots within the
vasculature. The term obstructions may include blood clot, plaque,
cholesterol, thrombus, naturally occurring foreign bodies (i.e., a
part of the body that is lodged within the lumen), a non-naturally
occurring foreign body (i.e., a portion of a medical device or
other non-naturally occurring substance lodged within the lumen.)
However, the devices are not limited to such applications and can
apply to any number of medical applications where elimination or
reduction of the number of connection points is desired.
[0008] In one variation of the devices described herein, the device
comprises a main bundle or group of wires that diverge to form a
device having various shapes but few or no connections points or
joints (where fabrication of such a construction is referred to as
"jointless").
[0009] The term shape (or shaped section), when applied to the
various shapes of the device, is intended to identify different
parts of the device where the wires/fibers form different sections
or portions of the device. Each such region or shape has a
structure that serves a different function of the device. In one
example of such a device, a first shape can be a connector portion
and a second shape can be a basket or mesh shape. In this case, the
first shape (the connector portion) has a different structure and
serves a different function than the second shape (the basket or
mesh shape). In another example, a first shape can be a connector
portion, a second shape can be a traversing section, and the third
shape can be a second connector shape. Again, each shape serves a
different function (although in this example the first and third
shapes may have similar structures). In most variations of the
device, adjacent shapes will have different structures or will be
separated by the wires that diverge/converge to form adjacent
shapes (e.g., two adjacent shapes, each forming connector shapes
but are separated by wires that traverse between the connector
shapes). The different shapes may not necessarily be spaced axially
along the device; instead, as shown below, two shapes may form a
single connector portion (e.g., see FIG. 6C).
[0010] In one variation, the device is adapted for delivery through
a catheter and includes a main bundle comprising a group of wires
having a first end extending through the catheter and a second end,
where the main bundle of wires diverge at the second end to form a
first shaped section, the first shaped section further comprises an
expanded profile and a reduced profile for delivery through the
catheter, a plurality of individual subsets of wires each diverging
from the first shaped section to form a second shaped section, and
where the individual subsets of wires converge to form a third
shaped section, where the third shaped section comprises an
expanded profile and a reduced profile for delivery through the
catheter, and where the convergence and divergence of wires occurs
without junctions between wires.
[0011] The term diverge includes uncoupling or separating of joined
wires. In addition, a group of wires that form a first shape may
all diverge to form a new composite shape. For example, a bundle of
wires may form a loop shape and ultimately bend to extend in a
direction substantially normal to the loop shape. In such a case,
the wires can be considered to diverge from the loop shape to form
a second shape.
[0012] The devices of the present invention typically include a
main bundle from which the wires extend. In most case, the main
bundle extends for a length sufficient to withdraw the device from
a body of a patient. Accordingly in such cases, the main bundle
shall extend through the length of a catheter. In alternate
constructions, the main bundle may be affixed to a single wire or
member. In such cases, the single wire or member is used to
manipulate the device, which allows shortening of the length of the
main bundle.
[0013] Devices of the present invention can incorporate any number
of wires of different characteristics including, but not limited
to, materials, shapes, sizes and/or diameters. Clearly, the number
of permutations of device configurations is significant. Providing
devices with such a composite construction allows for the
manipulation of the device's properties to suite the intended
application.
[0014] In an additional variation, the devices can also include a
basket or mesh shape structure that assists in the removal of
obstructions from the body. In some cases, these basket structures
are used as a capturing section. Although any number of shapes is
contemplated, a few examples of such shapes include a basket, a
filter, a bag, a coil, a helical wire structure, a mesh, a single
wound wire, and a plurality of crossing wires.
[0015] In some cases where the device is intended to remove
obstructions from the vasculature, the device and catheter may be
constructed to permit relative rotation of the ends of the device
such that upon rotation a portion of the device converts to a high
friction surface to aid in removing the obstruction.
[0016] As noted herein, the joint-less construction improves the
flexibility and strength of the device by eliminating joints,
connection points, or other attachment points. In addition, the
joint-less construction improves the ability of the device to be
delivered through a small microcatheter. As a result, the device
and microcatheter are able to access remote regions of the
vasculature.
[0017] The devices may be fabricated to be self-expanding upon
deployment from a catheter. Alternatively, the devices can be
constructed from shape-memory alloys such that they automatically
deploy upon reaching a pre-determined transition temperature.
[0018] When used in the vasculature to retrieve obstructions, the
devices may include a low friction mode (such as a set of parallel
wires, or wires extending axially along the lumen or vessel) that
converts to an increased friction mode (such as a compressed set of
wires acting on the obstruction or a twisted set of wires acting on
the obstruction). The increase in friction is an increase in the
friction between the obstruction and the device (as opposed to the
vessel wall. In some cases, the low friction mode is a low surface
area mode and the high friction mode is a high surface area mode.
When configured in the low friction mode, the device is better
suited to engage the obstruction without the undesirable effect of
prematurely mobilizing the obstruction or compacting the
obstruction (e.g., when wires are slid across the obstruction in a
transverse motion). Upon engaging the obstruction, the device will
conform to a high friction mode with respect to the obstruction (in
some cases the device will have an increased surface area mode).
This high friction mode permits the device to better grip the
obstruction for ultimate removal of the obstruction.
[0019] The operation of the devices and method described herein
secure the obstruction, overcome the elastic forces of the
obstruction, and then remove the obstruction from the anatomy
without losing or fractionating the obstruction. In one variation
of the invention, this is accomplished by the obstruction removal
device interacting with the obstruction in the following manner:
(1) a portion of the wires are delivered distal to the obstruction
by passing either through the obstruction or between the
obstruction and the vascular wall; (2) the traversing wires are
pulled proximally to engage a basket shaped section of the device
around the obstruction, the basket shaped section engages the
obstruction without causing significant mobilization of the
obstruction; (3) the device is pulled further proximally and the
surrounding portion now mobilizes the obstruction.
[0020] As shown below, variations of the devices have a
configuration that provides a path for a portion of the device to
surround the obstruction. The paths are made using sets or subsets
of wires that allow for low frictional translation of the device
over the obstruction without causing axial translation of the
obstruction. This mechanism is described in more detail below.
[0021] Once in the proper position, a portion of the device
increases the frictional contact with the obstruction to disperse
the pulling force more evenly across the obstruction. The increase
points of contact allow for removal of the obstruction through
tortuous anatomy while ensuring that the obstruction will not
escape the encapsulation.
[0022] It should be noted that reference to surrounding, capturing
or securing the obstruction includes partially and/or fully
surrounding, engulfing, encapsulating, and/or securing the
obstruction. In any case, a portion of the device engages the
obstruction prior to translation of the obstruction within the
lumen. As noted herein, a portion of the device may convert into a
surrounding section (e.g., when wires reorient to increase the
friction acting on the obstruction). Accordingly, these wires
convert into a surrounding section.
[0023] It should be noted that in some variations of the invention,
all or some of the device can be designed to increase their ability
to adhere to the obstruction. For example, the wires may be coupled
to an energy source (e.g., RF, ultrasonic, or thermal energy) to
"weld" to the obstruction. Application of energy to the device can
allow the surrounding portion to deform into the obstruction and
"embed" within the obstruction. Alternatively, the device can
impart a positive charge to the obstruction to partially liquefy
the obstruction sufficiently to allow for easier removal. In
another variation, a negative charge could be applied to further
build thrombus and nest the device for better pulling force. The
wires can be made stickier by use of a hydrophilic substance(s), or
by chemicals that would generate a chemical bond to the surface of
the obstruction. Alternatively, the filaments may reduce the
temperature of the obstruction to congeal or adhere to the
obstruction.
[0024] Additional devices and methods for treating ischemic stroke
are discussed in commonly assigned U.S. patent application Ser. No.
11/671,450 filed Feb. 5, 2007; Ser. No. 11/684,521 filed Mar. 9,
2007; Ser. No. 11/684,535 filed Mar. 9, 2007; Ser. No. 11/684,541
filed Mar. 9, 2007; Ser. No. 11/684,546 filed Mar. 9, 2007; and
Ser. No. 11/684,982 filed Mar. 12, 2007; the entirety of each of
which is incorporated by reference. The principles of the invention
as discussed herein may be applied to the above referenced cases to
produce devices useful in treating ischemic stroke. In other words,
the wire-shaped construction of devices according to present
invention may assume the shapes disclosed in the above-referenced
cases.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Each of the following figures diagrammatically illustrates
aspects of the invention. Variation of the invention from the
aspects shown in the figures is contemplated.
[0026] FIG. 1A illustrates an example of a device according to the
present invention when used in a system for removing obstructions
from body lumens.
[0027] FIG. 1B illustrates a first variation of the device having a
joint-less construction.
[0028] FIG. 1C illustrates another variation of a main bundle of
wires diverging in a joint-less construction.
[0029] FIG. 2A illustrates an example of an obstruction lodged
within a body lumen.
[0030] FIGS. 2B to 2F illustrate advancement of a catheter beyond
an obstruction and placement of a variation of the inventive device
around the obstruction.
[0031] FIGS. 2G to 2H illustrate devices according to the present
invention once converted to a high friction mode.
[0032] FIGS. 3A to 3B illustrate additional variations of the
inventive device having a basket or mesh structure formed from
diverging wires.
[0033] FIGS. 3C to 3D show positioning a variation of a device
distally to an obstruction to ultimately translate a basket shaped
section over the obstruction.
[0034] FIGS. 4A to 4B illustrate another variation of a portion a
device configured to convert from a low friction mode to a high
friction mode.
[0035] FIG. 5 illustrates an example of manufacturing a device by
orienting the wires on a planar fixture.
[0036] FIGS. 6A to 6D illustrate variations of the shaped sections
that can be formed from the wires forming the device.
[0037] FIG. 6E illustrates hooks, fibers, and/or barbs for
increasing the ability of the device to remove obstructions.
[0038] FIGS. 7A to 7C illustrate additional variations of shapes
for use in the devices according to the present invention.
[0039] FIGS. 8A to 8G also illustrate additional variations of
obstruction removal devices, focusing mainly on variations of the
surrounding portion.
[0040] FIGS. 9A to 9C show another variation of a medical device
having multiple bundles of wires where the wires diverge to form
capturing sections.
DETAILED DESCRIPTION
[0041] It is understood that the examples below discuss uses in the
cerebral vasculature (namely the arteries). However, unless
specifically noted, variations of the device and method are not
limited to use in the cerebral vasculature. Instead, the invention
may have applicability in various parts of the body. Moreover, the
invention may be used in various procedures where the benefits of
the method and/or device are desired.
[0042] FIG. 1A illustrates a system 10 for removing obstructions
from body lumens as described herein. In the illustrated example,
this variation of the system 10 is suited for removal of an
obstruction in the cerebral vasculature. Typically, the system 10
includes a catheter 12 microcatheter, sheath, guide-catheter, or
simple tube/sheath configuration for delivery of the obstruction
removal device to the target anatomy. The catheter should be
sufficient to deliver the device as discussed below. The catheter
12 may optionally include an inflatable balloon 18 for temporarily
blocking blood flow or for expanding the vessel to release the
obstruction.
[0043] It is noted that any number of catheters or microcatheters
maybe used to locate the catheter/microcatheter 12 carrying the
obstruction removal device (not illustrated) at the desired target
site. Such techniques are well understood standard interventional
catheterization techniques. Furthermore, the catheter 12 may be
coupled to auxiliary or support components 14, 16 (e.g., energy
controllers, power supplies, actuators for movement of the
device(s), vacuum sources, inflation sources, sources for
therapeutic substances, pressure monitoring, flow monitoring,
various bio-chemical sensors, bio-chemical substance, etc.) Again,
such components are within the scope of the system 10 described
herein.
[0044] In addition, devices of the present invention may be
packaged in kits including the components discussed above along
with guiding catheters, various devices that assist in the
stabilization or removal of the obstruction (e.g., proximal-assist
devices that holds the proximal end of the obstruction in place
preventing it from straying during removal or assisting in the
removal of the obstruction), balloon-tipped guide catheters,
dilators, etc.
[0045] FIG. 1B illustrates a first variation of a device according
to the features described herein. As shown, the device 200
generally includes a main bundle 202 comprising a group of
individual wires 204. The individual wires 204 may be comprised of
a number of different wires, or a single type of wire. Variations
of the wires 204 are discussed in detail below; however, the wires
204 can be strands, filaments, or any similar structure that is
able to be joined to form the device. The bundle 106 may be
braided, wrapped, twisted, or joined in any manner such that they
do not separate or become unbundled except where desired. As shown,
the main bundle 202 diverges to form a first shaped section 206. In
this particular example, the bundle 202 diverges in two sections
208, 210 which then diverge again to form the first shape 206.
[0046] Next, the wires 204 forming the first shape 206 diverge in
groups or subsets of wires 212, 214, 216, 218, to form a second
shaped section 220. Ultimately, the subsets of wires 212, 214, 216,
218 converge to form a third shaped section 224. The ends of the
wires 204 may terminate in the final shape of the device. In other
variations, the device is constructed such that the shapes formed
by the divergence and convergence of the wires are formed by the
center of the individual wires where all the ends of the wires are
located in the main bundle 202. In such a configuration, the device
will not contain any terminating ends. In such a case, the wires
forming the shapes are continuous and the device is completely
joint or connection free.
[0047] In the illustrated variation, the first shaped section and
third shaped section 206, 224 form loop shapes while the second
shaped section forms a series of traversing elements that extend
between the loops. When formed into traversing elements, the wires
extend substantially parallel to one another and normal to the
shaped sections so that they can span between the first and third
shaped sections.
[0048] As noted below, any number of shapes may be formed with this
joint-less construction. In addition, the devices described herein
may have any number of shaped sections. For example, in the
illustrated variation, the first and second 206, 224 shaped
sections form two loop type structures. However, the device may be
constructed such that the wires diverge to form any number of
looped shaped structures.
[0049] In any case, the individual wires 204 form a composite
device 200 having individual sections that can serve various
functions upon deployment of the device 200. The divergence and
convergence of the wires minimizes the numbers of joints or
connections that would otherwise be required to form the composite
shape. Such a configuration produces a smooth geometry given that
the wires forming the device 200 are continuous.
[0050] FIG. 1C illustrates a partial view of another variation of a
device 200 according to the present invention. In this variation,
the device 200 comprises a main bundle 202 where the main bundle
202 diverges to form the first shape 206. In contrast with the
device shown in FIG. 1B, the main bundle 206 does not diverge to
form sections 208, 210 prior to forming the first shape 206.
[0051] It is noted that any number of shapes, configurations, as
well as any number of joined wires may be contemplated to form
devices under the present disclosure. However, variations of the
invention include selecting a number of wires 204 to produce
specific structural properties to the device. For example, if it is
desired that each subset 212, 214, 216, 218, have at least two
wires, then naturally the first section, third section, and main
bundle 202 must have at least two wires. However, in some cases, it
may be desired that these sections have additional wires to impart
the required characteristics. For example, in the illustrated
variation, the main bundle may comprise any number of wires that do
not diverge to form subsequent shapes in the device. In other
words, not all of the wires forming a section are required to
diverge to form an adjacent section. Instead, these non-diverging
wires may simply "loop" back away from the device. In an additional
variation, one or more wires may diverge to form a first shape and
part of a second shape. Then the wires can loop back to converge
again with the main bundle.
[0052] Of course, the opposite construction is also within the
scope of this disclosure. Namely, that each wire from the main
bundle diverges to form an adjacent section or shape.
[0053] FIGS. 2A to 2F show one example of the deployment of a basic
structure of a device according to the present invention about an
obstruction in a vessel. The figures are intended to demonstrate
the initial placement of the device immediately prior to removal of
the obstruction either using a filter or by torquing, rotating
and/or twisting the device ends relative to one another. This
action converts the device from a low friction device to a high
friction device (where the low/high friction is the friction
between the device and the obstruction). This action may also be
referred to as a low surface area mode converting to a high surface
area mode (in cases where the device extends beyond the obstruction
and relative motion between ends of the device causes the device to
shrink in axial length as it is twisted.)
[0054] FIG. 2A illustrates an example of an obstruction 2 lodged
within a body lumen or vessel 6. In the case where the vessel is a
cerebral artery, the obstruction may result in an ischemic stroke.
Using standard interventional catheterization techniques, a
microcatheter 102 and guidewire 104 traverse the obstruction. The
microcatheter 102 may be advanced through the obstruction 2.
Alternatively, the microcatheter 102 may "push" aside the
obstruction and is advanced around the obstruction. In any case,
the microcatheter 102 travels from the near end 3 (or proximal
side) of the obstruction 2 to the far end 4 (or distal side) of the
obstruction 2. It is noted that the catheter 102 may be centered or
off-center with respect to the obstruction 2. Furthermore, the
device may or may not be used with a guidewire to navigate to the
site and traverse the obstruction.
[0055] FIG. 2B shows another variation where a microcatheter 102
traverses the obstruction 2 between the wall of the vessel 6 and
the obstruction 2. As shown, the open end of the microcatheter 102
is distal to the obstruction 2 and is now positioned to deploy
devices for removal of the obstruction 2. This variation shows the
device after removal of any guidewire. However, some variations of
the device may be placed without an accompanying guidewire.
Moreover, the structures discussed herein may be directly
incorporated into a guidewire assembly where deployment may require
a sheath or other covering to release the components from
constraint.
[0056] FIG. 2C illustrates deployment of a portion of the device
200 from within the microcatheter 102 distal to the obstruction 2.
In this example, the third shaped section 224 deploys distally to
the obstruction 2. As noted herein, depending on the properties of
the device 200 as determined by the types of wires used, third
shaped section 224 can be self-expanding such that it assumes, or
moves towards, the expanded profile (as shown) upon deployment from
the constraint of the microcatheter 102. Alternatively, the
third-shaped section 224 can be actuated to assume the shape (e.g.,
upon reaching a transition temperature where one or more wires
comprise a shape memory alloy).
[0057] FIG. 2D shows withdrawal of the microcatheter 102 to the
proximal side 3 of the obstruction 2. The spacing between the third
shaped section 224 and the obstruction 2 may vary. In some cases
the third shaped section 224 will move closer towards the
obstruction 2 during spacing of the remainder of the device as
discussed below. The third shaped section 224 remains in place
either using the inherent friction of the wires against the vessels
and/or obstruction 2. Alternatively, or in combination, a wire-type
member (not shown) may provide an opposing force against the third
shaped section 224 as the catheter 102 moves proximal to the
obstruction 2.
[0058] As noted above, this variation of the device 200 include a
plurality of subsets 212, 214, 216, 218 that traverse between the
first and third shaped sections 206, 224. As shown in FIG. 2E,
eventually, second shaped section 220 spans across the obstruction
2 as shown.
[0059] FIG. 2F illustrates the device 200 after the second shaped
section 220 separate about the obstruction 2. This action causes
the second shaped section 220 to span the obstruction 2 while
reorienting towards an exterior of the obstruction 2. The subsets
of wires may remain partially or fully within the obstruction 2.
However, given that the filaments are spaced about the loops formed
by the first shaped section 206 and third shaped section 224, the
filaments shall separate radially over the obstruction allowing for
the subsequent ensnaring and removal of the obstruction 2.
[0060] Spacing the subsets that traverse across the obstruction can
occur via a number of modes such as tensioning, expanding,
spreading separating and/or withdrawing the wires. Regardless of
the mode used, the subsets are intended to be positioned at or near
a surface of the obstruction so that they can reduce the effects of
any friction between the obstruction and the lumen or vessel
wall.
[0061] FIGS. 2G to 2H illustrates examples of the device 200 that
ensnare the obstruction 2 after the device is in the configuration
demonstrated by above. In these cases, the devices 200 transform
from a low friction mode to a higher friction mode for removal of
the obstruction 2. FIGS. 2G to 2H illustrate rotation of the ends
of the device 206 and 224 relative to one another. The resulting
action converts the device 200 to a high friction mode to ensnare
the obstruction 2 within the traversing section formed by the wires
in the second shaped section 220. As noted herein, either connector
may rotate while another connector remains stationary.
Alternatively, each connector may rotate with the rate of rotation
for one connector being slower than another. In yet another
variation, each connector may be rotated in opposite
directions.
[0062] Although the variation shows only four individual subsets of
wires traversing across between the first and third shaped sections
206 and 224 any number subsets may be used so long as the rotation
converts the wires into a relatively increased friction mode as
compared to the low friction mode (when the subsets are in a
parallel configuration). The low friction mode is represented by
FIG. 2F. FIG. 2G illustrates a device in a high friction mode where
the subsets of wires forming the second shaped section 220 twist
and cross one another over the length of the obstruction 2. It
should be noted that additional shaped sections 206, 220, and/or
224 may be required to produce the crossing pattern shown in FIG.
2G, or other preferred patterns when the device is twisted to
convert to a high friction mode.
[0063] In contrast, the device 200 may be configured to transform
as shown in FIG. 2H. In this case, conversion of the device 200
causes twisting at points 116 where the twist points 116 are
proximal and distal to the obstruction 2. To accomplish this, the
device 200 can be selected to have a length greater than the
targeted obstruction 2. Upon rotation, the second shaped section
220 formed from the subsets of wires that traverse across
obstruction remain uncrossed over the length of the obstruction 2.
In some cases, the second shaped section 220 can experience some
twisting and will not remain parallel. The relative motion of the
ends 206 and 224 as well as the twist points 116 causes the second
shaped section 220 to exert a compressive force on the obstruction
2 without crossing one another over the length of the obstruction.
Accordingly, while the surface area in contact between the second
shaped section 220 and obstruction 2 remains relatively the same,
the compressive action of the second shaped section 220 onto the
obstruction converts the device 200 to a high friction mode on the
obstruction.
[0064] The rotation of the ends of the device 206, 224 can be
performed in any number of ways as known to those skilled in the
art. In either case, the obstruction 2 becomes ensnared (and/or
encapsulated) and can be removed from the body.
[0065] FIG. 3A illustrates another variation of a device where the
wires 204 diverge from an end of the device 200 to form a basket
226 shape or structure. The basket structure 226 may also be
referred to as a filter or surrounding portion. In variations of
the device, the basket 226 is sufficiently permeable to allow blood
flow therethrough. As noted above, basket 226 may be any structure
that covers, encapsulates, engulfs, and/or ensnares the obstruction
either fully or partially. Accordingly, although the basket 226 is
illustrated as a filter/bag, the wires may diverge to form a coil,
helical shape, other mesh structure, or any other structure that
may translate or remove the obstruction 2 once the frictional
component is addressed.
[0066] FIG. 3B shows a top view of a variation of a device 200
showing another configuration of a basket shape 226 formed by wires
that diverge from an end of the device 200. In this variation, the
wires 204 diverge in subsets 228 from the third shaped section 224.
However, the subsets 228 continue to diverge at the far end of the
device to form a mesh region 230 (i.e., an area of dense wire
coverage). This mesh region 230 can increase the contact area
between the wires 204 and the obstruction, which assists in removal
of the obstruction. Divergence of wires could occur multiple times
as wires head to the distal region of basket, creating a basket
with denser and denser coverage moving distally.
[0067] FIG. 3C depicts a variation of the device similar to that of
FIG. 3A. As shown, the device 200 is deployed distally to the
obstruction 2 As shown, this deployment allows the subsets of wires
that extend along the device 200 to expand within the vessel 6
prior to contacting the occlusion 2.
[0068] Next, as shown in FIG. 3D, the device 200 is pulled over the
occlusion 2. As noted herein, the subsets of wires that form the
second shaped portion 220 addresses the frictional forces that act
between the obstruction and the vessel wall. Conventional devices
that provide a bag attached to a wire (such as a vascular filter or
distal protection device), are typically unable to remove the
obstruction because they cannot overcome these frictional forces
that lodge the clot against the vessel wall. Typically, such
conventional devices are only designed to "catch" free floating
clots. Providing low friction with respect to the clot and the
vessel allows for positioning of the device without disrupting or
further compacting the clot against the vessel wall. Once the wires
of the device surround or are spaced about the obstruction, they
reduce the friction between the clot and vessel wall by reducing
points of contact. Once these wires surround the clot, they permit
translation of the device to permit a basket shaped section 226 to
surround the obstruction for removal. Eventually, the device 200 is
pulled so that the basket shaped section 226 captures the
obstruction 2 allowing it to be removed.
[0069] FIG. 4A illustrates a variation of a device 200 where the
first shaped section is a loop shaped member 206 and the third
shaped section 224 forms a closed end where the wires converge. As
shown, subsets 212, 214, 216, 218 diverge from the first shaped
section 206 and extend substantially parallel to the loop. Rather
than converging to form another loop, the subsets converge to form
a shaped section 224 having a closed end configuration. FIG. 4B
illustrates the variation of FIG. 4A after it converts to a high
friction mode over the obstruction 2 via rotation of the first
shaped section 206. As with other variations, the number of subsets
may vary as needed. In addition, the subsets of wires 212, 214,
216, 218 can further diverge to form a denser mesh pattern at or
towards the third shaped section 224.
[0070] As shown, rotation of the shaped section 206 forms a twist
point 116 proximal to the obstruction 2. In some cases, the subsets
of wires 212, 214, 216, 218 can experience some twisting and may
not remain parallel. The rotation of the shaped section 206 as well
as the twist point 116 causes the subsets of wires 212, 214, 216,
218 to exert a compressive force on the obstruction 2 without
crossing one another over the length of the obstruction.
Accordingly, while the surface area in contact between the subsets
of wires 212, 214, 216, 218 and obstruction 2 remains relatively
the same, the compressive action of the subsets of wires onto the
obstruction converts the device 200 to a high friction mode on the
obstruction.
[0071] FIG. 5 shows one example of a method for constructing
devices according to the present invention. A main bundle of wires
202 is brought into a fixture (not shown). The fixture permits
routing of the wires in the pattern as shown. In this particular
variation, the main bundle comprises 8 wires. However, number of
wires is intended for exemplary purposes only. Clearly, any number
of wires may be used. As shown the wires diverge in the region
marked 232 to form four separate subsets of wires 212, 214, 216,
218. Again, in this example, each subset of wire comprises 2
individual wires. This configuration is for illustrative purposes
as the number of wires in each subset is not required to be the
same for all.
[0072] Next, the wires converge in the region marked as 234. It is
noted that if the device is constructed on a planar fixture, the
wires (once oriented) will be wrapped around a cylindrical
structure and heat set to impart the shapes shown above.
Accordingly, the regions marked by 232 and 234 assume partial loop
shapes as the planar wire assembly is wrapped around the
cylindrical fixture. In alternate variations, the wires may be
oriented on a cylindrical fixture and heat set into a final shape.
Doing so obviously eliminates the need to wrap the planar wire
assembly about a cylindrical structure.
[0073] As shown, once the wires form the region marked as 234, they
diverge once again to form a basket shaped section or filter 226 as
discussed above. Accordingly, upon wrapping the device wires, the
region marked as 234 assumes a loop shaped section. The wires
forming the basket shaped section or filter 226 can either
terminate at the end of the basket or filter 226. Alternatively,
the wires can be looped around such that they eventually extend
back through the main bundle 202 or loop back and and terminate in
any portion of the device.
[0074] The above described wire form construction allows for a
number of configurations depending on the particular application.
For example, the individual wires 204 may themselves comprise a
bundle of smaller wires or filaments. In addition, the wires can be
selected from materials such as stainless steel, titanium,
platinum, gold, iridium, tantalum, nitinol, and/or polymeric
strands. In addition, the wires used in a device may comprise a
heterogeneous structure by using combinations of wires of different
materials to produce a device having the particular desired
properties. For example, one or more wires in the device may
comprise a shape memory or superelastic alloy to impart
predetermined shapes or resiliency to the device. In some
variations, the mechanical properties of select wires can be
altered. In such a case, the select wires can be treated to alter
properties including: brittleness, ductility, elasticity, hardness,
malleability, plasticity, strength, and toughness.
[0075] In addition, the device may include a number of radiopaque
wires, such as gold and platinum for improved visibility under
fluoroscopic imaging. In other words, any combination of materials
may be incorporated into the device. In addition to the materials,
the size of the wires may vary as needed. For example, the
diameters of the wires may be the same or may vary as needed.
[0076] In addition, the individual wires may have cross-sectional
shapes ranging from circular, oval, d-shaped, rectangular shape,
etc. Moreover, the device is not limited to having wires having the
same cross-sectional shape. Instead, the device can have wires
having different cross-sectional shapes. To illustrate one such
example, a device can have 8-12 wires made of 0.003'' round
superelastic material (e.g., nitinol). The device may additionally
have 2-4 wires made from 0.002'' platinum for fluoroscopy. Of the
8-12 nitinol wires, 1-4 of these wires can be made of a larger
diameter or different cross-section to increase the overall
strength of the device. Finally, a couple of polymer fibers can be
added where the fibers have a desired surface property for clot
adherence, etc. Such a combination of wires provides a composite
device with properties not conventionally possible in view of other
formation means (such as laser cutting or etching the shape from a
tube or joining materials with welds, etc.). Clearly, any number of
permutations is possible given the principles of the invention.
[0077] In another example, the device may be fabricated from wires
formed from a polymeric material or composite blend of polymeric
materials. The polymeric composite can be selected such that it is
very floppy until it is exposed to either the body fluids and or
some other delivered activator that causes the polymer to further
polymerize or stiffen for strength. Various coatings could protect
the polymer from further polymerizing before the device is properly
placed. The coatings could provide a specific duration for
placement (e.g., 5 minutes) after which the covering degrades or is
activated with an agent (that doesn't affect the surrounding
tissues) allowing the device to increase in stiffness so that it
doesn't stretch as the thrombus is pulled out. For example, shape
memory polymers would allow the device to increase in
stiffness.
[0078] As discussed herein, the shaped section connectors may be
other structures than loops. Moreover, variations of the invention
include connectors that may be drawn down to a smaller size to
facilitate removal from the body after securing the obstruction.
This may be accomplished by torquing the device or part thereof, by
re-sheathing part or all of the device or by any mechanical means
designed into the features of the device itself. Any of these
actions, or combination thereof, may also serve to compress or
decrease the diameter of the obstruction itself to facilitate
removal from the body.
[0079] As with the above examples, the illustrated variation shown
above, the shaped portions are formed in a loop or partial loop
shape. However, as described herein, the connectors may also
comprise various alternate shapes (e.g., a circle, an arcuate
shape, a partial circular shape, a loop, an oval, a square, a
rectangle, a polygon, an overlapping loop, a pair of semi-circles,
a flower shape, and a FIG. 8, other shapes, etc.) FIGS. 6A to 6D
illustrate some possible shapes for use in the device. The various
shapes may be heat set to be either self expanding (i.e.,
superelastic) or the use of shape memory alloys can allow for the
device to assume the particular shape upon reaching a desired
transition temperature. In certain cases, such as where the shape
is an overlapping loop, a pair of semi-circles, a flower shape, a
FIG. 8, or other complex/discontinuous shape, such a shape may be
formed by a single bundle or by one or more separate portions of
wire that diverge from the main bundle.
[0080] FIG. 6A illustrates a main bundle of wires 202 that diverge
in three arcuate shaped portions 242, 244, 246. Naturally, the
device may have more or less arcuate shaped sections. In this
illustration, the segments forming the arcuate 242, 244, 246 shaped
portions may simply bend to form segments that traverse across the
device (as shown above.) However, such traversing sections are
omitted to illustrate the arcuate shape.
[0081] FIG. 6B illustrates a main bundle 202 that ultimately
diverges to form an overlapping loop shape 248. As shown, the ends
of the overlapping loop may then proceed to form the traversing
subsets 212, 214 discussed above. In addition, additional subsets
of wires may diverge from a location other than the end of the
overlapping loop shape 248.
[0082] FIG. 6C illustrates a main bundle that diverges to form two
semi-circular or partial circular shapes 250, 252. In this
variation, the two shapes are located along the same axial section
of the device but the shapes are separate. Again, the ends of the
partial circular shapes 250, 252 may diverge to form the traversing
section of the device. Alternatively, the traversing wires can come
from other locations.
[0083] FIG. 6D illustrates a main bundle 202 that diverges to form
a "figure-8" shape. As with other variations, additional subsets
(not shown) of wires may diverge from the "figure-8" shape to form
the traversing subsets. In addition, flower shaped sections may be
formed by the use of additional circular shapes that form the
petals of the flower shape or via the use of multiple "figure-8"
shapes.
[0084] The exemplary shapes discussed above permit the shaped
section to adjust in diameter in response to placement in varying
diameters of body lumens. It is noted that a device may have
different shaped sections on different ends of the device.
[0085] While many different shapes are contemplated to be within
the scope of this disclosure, the shapes will depend upon the
ultimate application of the device. As noted herein, the
illustrated examples have particular applicability in retrieving
obstructions from the vasculature. Accordingly, for these
applications the shaped sections should form a shape so that they
can expand against a vessel wall without causing trauma to the
vessel. For example, upon release from the catheter, the shaped
section can assume their resting shape and expand within the
vessel. The resting shape can be constructed to have a size
slightly greater than that of the vessel. Sizing the device
relative to the target vessel may assist in placing the parts of
the device against a vessel.
[0086] In an additional aspect, the shaped sections may be designed
to have an unconstrained shape that is larger than the intended
target vessel or simply different than a cross sectional profile of
the intended vessel (i.e., not circular or tubular, but e.g.,
linear or other different shape). In such an example, as the shaped
section is released from the delivery catheter, the shape section
attempts to return to the unconstrained shape. In those variations
where the unconstrained shape is different from the circular
profile of the vessel, the leading wire assumes a shape that
accommodates the vessel but is more rigid and stable since its
unconstrained shape is entirely different from that of the vessel.
In other words, the shaped section continually exerts an outward
force on the vessel.
[0087] In yet another aspect, the shaped sections shown herein may
not necessarily lie in the same plane. Instead, they can be axially
spaced by an offset. One benefit of constructing the device to have
non-planar shaped section is that the configuration might allow for
delivery of the device delivered via a smaller microcatheter
because the shaped sections do not interfere with one another when
collapsed to fit within the microcatheter.
[0088] Another aspect applicable to all variations of the devices
is to configure the devices (whether the traversing filament or the
surrounding portion) for better adherence to the obstruction. One
such mode includes the use of coatings that bond to certain clots
(or other materials causing the obstruction.) For example, the
wires may be coated with a hydrogel or adhesive that bonds to a
thrombus. Accordingly, as the device secures about a clot, the
combination of the additive and the mechanical structure of the
device may improve the effectiveness of the device in removing the
obstruction.
[0089] Such improvements may also be mechanical or structural. For
example, as shown in FIG. 6E, the traversing members may have
hooks, fibers, or barbs 154 that grip into the obstruction when the
device converts to a high friction mode. The hooks, fibers, or
barbs 154 incorporated into any portion of the device. However, it
will be important that such features do not hinder the ability of
the practitioner to remove the device from the body.
[0090] In addition to additives, the device can be coupled to an RF
or other power source (such as 14 or 16 in FIG. 1), to allow
current, ultrasound or RF energy to transmit through the device and
induce clotting or cause additional coagulation of a clot or other
the obstruction.
[0091] The methods described herein may also include treating the
obstruction prior to attempting to remove the obstruction. Such a
treatment can include applying a chemical or pharmaceutical agent
with the goal of making the occlusion shrink or to make it more
rigid for easier removal. Such agents include, but are not limited
to chemotherapy drugs, or solutions, a mild formalin, or aldehyde
solution.
[0092] Although not illustrated, the devices and methods described
herein may also be useful in removing obstructions lodged within
bifurcations in the anatomy. Generally, bifurcations greatly
increase the frictional forces on the obstructions since the
obstruction tends to be lodged in both branching sections of the
bifurcation. In such cases, the use of the presently described
devices and methods may also include an additional "puller" device
that advances beyond the portion of the obstruction partially
located in the bifurcated vessel.
[0093] As for other details of the present invention, materials and
manufacturing techniques may be employed as within the level of
those with skill in the relevant art. The same may hold true with
respect to method-based aspects of the invention in terms of
additional acts that are commonly or logically employed. In
addition, though the invention has been described in reference to
several examples, optionally incorporating various features, the
invention is not to be limited to that which is described or
indicated as contemplated with respect to each variation of the
invention.
[0094] FIGS. 7A to 7C illustrate additional variations of
obstruction removal devices. In these variations, the wires may
diverge from the main wire bundle 202 to form any number of shapes
and structures and specifically not form loop or the shaped
sections discussed above. For example, in FIGS. 7A to 7B the wires
diverge to ultimately form a basket or filter shape 226.
[0095] FIGS. 8A to 8F illustrate various additional configurations
for construction of join-less devices 200. As shown, the main
bundle of wires 202 diverges so that one or more wires forms the
illustrated shapes.
[0096] FIGS. 9A to 9C show another variation of a medical device
according to the principles of the invention. As shown, the device
200 comprises a first and second main bundles 202, where the main
bundles comprise a plurality of wires. The devices further include
a first shape and second shapes 206 formed by a divergence of the
plurality of wires into a plurality of individual first subsets of
wires. In these variations, the wires diverge to form a network of
individual single wires as shown in region 226. The shapes form a
three dimensional structure that is useful for removal of
obstruction from within the body. In FIG. 9B, each shape comprises
a structure that forms a portion of the basket where a network of
wires forms an end of the basket. In FIGS. 9A and 9C the network of
wires forms the entire basket.
[0097] As noted above, the shapes 206 may range from a circle, an
arcuate shape, a partial circular shape, a loop, an oval, a square,
a rectangle, a polygon, an overlapping loop, a pair of
semi-circles, a flower shape, and a FIG. 8 (as shown above).
[0098] Various changes may be made to the invention described and
equivalents (whether recited herein or not included for the sake of
some brevity) may be substituted without departing from the true
spirit and scope of the invention. Also, any optional feature of
the inventive variations may be set forth and claimed
independently, or in combination with any one or more of the
features described herein. Accordingly, the invention contemplates
combinations of various aspects of the embodiments or combinations
of the embodiments themselves, where possible. Reference to a
singular item, includes the possibility that there are plural of
the same items present. More specifically, as used herein and in
the appended claims, the singular forms "a," "and," "said," and
"the" include plural references unless the context clearly dictates
otherwise.
* * * * *